1. Field of the Invention
The present invention generally relates to notes detector which receives an input of a musical instrument sound or a human voice, extracts its pitch, determines its note and generates a musical sound electronically in accordance with the result of the determination. More particularly, the present invention relates to a note detector which receives a plurality of musical instrument sounds and/or human voices, including a chord to perform note detecting operations and to an electronic instrument with such a note detector.
2. Description of the Related Art
Conventionally, techniques are provided of receiving an input of a musical instrumental sound or a human voice, extracting its pitch, determining its note, and printing out the result in the form of a score, or encoding and recording the series of results of determination in order to execute an automatic performance by generating other musical instrument sounds (for example, as disclosed in Published Unexamined Japanese Patent Applications Sho 57-692 and Sho 58-97179).
Actually, such prior arts can only handle an input of a single sound basically and does not allow for an input of a plurality of sounds including a chord.
It was proposed that the name of a chord is detected in response to reception of an input of the chord and displayed in accordance with a signal indicative of the name of the chord (Published Unexamined Japanese Utility Model Application Sho 60-26091).
This application discloses provision of analog bandpass filters equal in number to notes, holding the respective peak outputs from those filters, and using the larger ones of the peak outputs as more powerful candidates for the components of a chord using a level detector.
The technique of using such analog filters has the problem that the result of the determination would be likely to fluctuate or be unstable due to the ambient temperature or that the circuit structure would be large-scaled, disadvantageously.